The objective of this proposal is to implement Falcon signature verification directly within a Soroban smart contract. To frame the work, we include a brief overview of the Falcon signature scheme and its cryptographic components below.
Previous research demonstrates that Falcon’s original SHAKE-based hashing can be replaced by Keccak to lower computational overhead. As part of this project, we will benchmark both approaches and identify which hash function—SHAKE or Keccak—provides the best cost-efficiency on Stellar.
Our implementation will use the following references as primary sources:
FALCON is a digital signature system that comes from the family of lattice-based cryptography. Rather than depending on classical number-theoretic assumptions, it uses structured lattices derived from the NTRU construction. The scheme follows the signing approach introduced by Gentry, Peikert, and Vaikuntanathan, but adapts it with a Fourier-domain sampler that efficiently produces short lattice vectors. Its security relies on the difficulty of finding short solutions in NTRU lattices — a problem with no known efficient classical or quantum algorithms.
Main Principles
Falcon follows the “hash-then-sign” paradigm, replacing RSA-style operations with lattice computations. Security comes from the hardness of identifying small vectors in high-dimensional NTRU lattices and from trapdoor information that enables controlled Gaussian sampling. These elements together provide compact, fast signatures.
Key Generation
Producing a Signature
Verification